Premium
Hippocampal output area CA1 broadcasts a generalized novelty signal during an object‐place recognition task
Author(s) -
Larkin Margaret Carr,
Lykken Christine,
Tye Lynne D.,
Wickelgren Jeanette Graham,
Frank Loren M.
Publication year - 2014
Publication title -
hippocampus
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.767
H-Index - 155
eISSN - 1098-1063
pISSN - 1050-9631
DOI - 10.1002/hipo.22268
Subject(s) - novelty , hippocampal formation , place cell , hippocampus , neuroscience , task (project management) , object (grammar) , encode , computer science , psychology , artificial intelligence , biology , social psychology , biochemistry , management , economics , gene
Animals display an innate preference for novelty, spending more time exploring both novel objects and familiar objects in novel locations. This increase in exploration is thought to allow the animal to gather the information necessary to encode new experiences. Despite extensive evidence that increased exploration following spatial change requires the hippocampus, the pattern of hippocampal activity that supports this behavior remains unknown. We examined activity in hippocampal output area CA1 and one synapse upstream in area CA3 while freely behaving rats performed an object‐place recognition task. We found that the presence of novelty substantially altered activity in CA1, but not in CA3. During exploration of displaced familiar objects and novel objects in unexpected locations, CA1 place cells showed robust increases in firing rate. These firing rate increases persisted during sharp wave ripples, when place cell representations of previous experiences are replayed. Unexpectedly, increases in CA1 activity were not spatially restricted to regions of the environment that underwent change, indicating a generalized novelty signal. We suggest that hippocampal area CA1 broadcasts the presence of novelty, rather than signaling what is novel, and simultaneously becomes more plastic, allowing the integration of new information into previously stored memories. © 2014 Wiley Periodicals, Inc.